Rev. Biol. Trop., 41 (3): 729-753,1993 Revision of the New World species of Ommatius Wiedemann (Diptera: Asilidae): the neotropical costatus species group A. G. Scarbrough Department oC Biologica1 Sciences, Towson State University, Baltimore, MD 21204 USA. (Rec.19-1-1993. Acep. 2-VI-1993) Abstracl: Fourleen species of New World Ommalius Wiedemann are assigned to me coslalus species group. Characlers diagnostic of me group and of each species are described and illuSlrated, and keys 10 me species are presented. The new species O. achaelus. O. complanalus. O. denlalus. O. didymus. O. humalus. O. incurvalus. O. spinosus. and O. IUICatusare described. O. amula Curran and O. coslalusRondani are redescribed. Data are added 10 existing descriptions oC O. alexanderi. O. orellOquellSis. O. oreophilus. and O. piliferous. LectolypeS are designated for O. coslalus [=0. barbiellinii Curran, NEW SYNONYMYj and O. orellOquellSisBigot (=0. irifraclusScarbrough, NEW SYNONYMYj. O. spalulalus.a similar species, is compared wím me coslalus group. Key words: Ommalius.Ommatinae, asilids,robbcr flies, Díptera, coslalusspecies group, neotropical. Ommatius Wiedemann is one of the most here, increasing the number of neotropical widely distributed genera of the family species to 66. Asilidae, with about 200 species occurring in subtropical and tropical regions (Hull 1962). MATERIAL AND METHODS Fifty-eight neotropicaI species are presentIy known (Martín and Papavero 1970, Scarbrough General methodoIogy used in this study 1990, Scarbrough and Poinar 1992); 28modern foIlows that by Scarbrough (1990). Descriptive and two extánt species from the West Indies, 15 terminology foIlows that in McAlpine (1981). from Mexico .and Mesoameriea and 13 from Figures 1-11. 34 and 35 indicate terminology South America. Another 50 or more for structures of the terminalia, wing and mid neotropicaI species, in at least6 species groups, femur. Hind tibiae and characters of the remain to be described and reported lO science. terminalia are illustrated at the same scale. To This paper, which assigns 14 species to the conserve space, scale lengths associated with costatus species group, represents Part II of a these structures are listed only once in the series revising the New World Ommatius caption of Figures 1-11. Descriptions and Wiedemann. Part 1assigned eight spccies to the redeseriptions are composites of aH specimens pumilus species group (Scarbrough 1990). The in each species series. O. alexanderi is costatus species group ineludes six previously described in detail while only significant known species: O. oreophilus Farr and O . differences are included for the remaining alexanderi Farr (Jamaica, Farr 1965), and O . species. Characters omitted in the latter are piliferous Scarbrough (Cuba, Scarbrough essentiaIly identical to those Usted under O . 1985b); O. amula Curran (Mexico, Curran alexanderi. Only significant differences of 1928), O. coslatus Rondani (Brazil, Rondani characters areUsted for females. 1850), and O. orenoquensis Bigot (Guiana, The foIlowing ratios are used in the Bigot 1876). Eight new species are reported descriptions, and are defined here for the 730 REVISTA DE BIOLOGIA 1ROPICAL convenience of the user. Face-to-head ratio Pesquisas da Amazonia, Manaus, Brazil; F. (FHWR) is the width of face at antenna/width Fernandez Yepes, (IZA) Instituto de Zoología of head (greatest width as measured Agrícola, University of Central Venezuela, horizontalJy from outer margin of one eye to Maracay; Donald Webb, (INHS) Illinois the other); width-to-Iength ratio of flagellum Natural History Survey, Champaign, ILL.; (FWLR) is the greatest lateral width/length (INBIO) Instituto Nacional de Biodiversidad of from base to apex; width-to-Iength of hind Costa Rica; (LJB) Larry Bezark, California femur (HFW LR) is the greatest vertical Department of Agriculture, Sacramento, CA.; width/dorsal length from the apex of the femur Charles L. Hogue, (LANHM) Los Angeles to the trochanter. Ratios are averages of 15 County Natural History Museum, CA.; J. specimens of each sex whenever possible. AH Manuel Ay ala L., (MAL) IsIe de Margarita, specimens were measured and averages Venezuela; D. J. Furth, (MCZ) Museum of calculated when the number of specimens in Comparative Zoology, Cambridge, MA.; Mike the series was less than 15. Ivie, (MIV ) Montana State University, Collection and locality data of new species Bozeman, MT.; Nelson Papavero, (MZSP) are standardized and Usted sequentially Museo de Zoologia, Universidade de Sao whenever possible, i. e. by country, sexes, Paulo, Brazil; C. A. Triplehorn, (OSU) Ohio numbers, state or province, specific location, State University, Columbus, OH.; D. Spencer elevation, date, and coIlector. Acronyms of Smith & George C. M. McGavin, (OXF) Hope museums oc private collections storing the Entomological Museum, Oxford, England; specimens are placed in parentheses following Donald Azuma, (PAS) Philadelphia Academy the locality data of each specimen or a series of of Science, Philadelphia, PA.; Hilda Atice de specimens. Curators and acronyms for O. Gasta!, (RGSZ) Museu de Ciencias Naturais collections are as follows: David Grimaldi, da Río Grande du Sol, Porto Alegre, Brazíl; (AMNH) American Museum of Natural Thomas H. Farr, (SMIJ) Science Museum, History, New York; A. G. Scarbrough, (AGS) Institute of Jamaica, Kingston, Jamaica; Todd Towson State University, Baltimore; K. V. G. Shelly, (TSC) Honolulu, HI.; R. O. Schuster, Smith & J. E. Chainey, (BMNH) Natural (UCD) University of California, Davis, CA.; History Museum, London, England; C. V. Saul Frommer, (UCR) Universíty of California, Riley, (B YU) Brigham Young University, Ríverside, CA.; L. Fernando Jiron, (UCRM) Provo, UT.; Norman Penny, (CAS) (California Universidad de Costa Rica, Ciudad Academy of Sciences, San Francisco, CA.; P. P. Universitaria, Rodrigo Facio, Costa Rica; Parrillo, (CFMNH) Chicago Field Museum of Antonio Rolondo, (UDT) Museo di Zoología, Natural History; IL.; Monty Wood & P. LaClair, DelIa Universito, Torino, Italia; G. W. Byers & (CNC) Canadian National Collection, Ottawa, R. W. Brooks, (UKN) University of Kansas, Canada: Chen W. Young, (CMNH) Carnegie Manhattan, KN.; F. Christian Thompson, Museum of Natural History, Pittsburgh, PA.; (USNM) United States National Museum of Jerry A. PoweIl, (CIS) University of California, Natural Hístory, Washington, D. C.; W. J. Berkeley, CA.; L. L. Pechuman, (COR) Cornell Hanson, (USU) Utah State Uníversity, Logan, University, lthaca, N. Y.; Eric M. Fisher, UT.; Roberto A. Zucchi, (USPP) Universidad (EMF) California Department of Agriculture, de Sao Paulo, Campus de Piracicaba, Sao Sacramento, CA.; Vanda H. P. Bueno, (ESAL) Paulo, Brazil Escola Superior de Agriculture de Lavras, Lavras, Brazil; Henry A. Hespenheide, (HAH) costatus species group University of California, Los Angeles, CA.; L. Tsacas, (NMNH) Museum National D'Historie Members of this species group are Naturelle, Paris, France; Howard L. Weems, recognized by a lancet or spear-shaped (FSCA) Florida State Collection of Arthropods, flagellum, conspicuous marginal scutellar Gainesville, FL.; Renato Contin Marinoni, bristles except O. achaetus, and one-three thin, (FUPC) Federal Universidade de Parana, proclinate postocular bristles on each side of Curitiba, Brazil; Abraham Willink, (IML) the head. In addition, the ventral setae of the Instituto Lillo Miguel, Tucuman, Argentina; J. fore femora and the posteroventral setae of the A. Rafael, (INPA) Instituto Nacional de mid femora are conspeciously long. SCARBROUGH:New World Ommalius 731 Males are recognized by the presence of a characters in combination. At least threeWest long, thin lO bristlypreapical, dorsoposterior seta Indian species (Scarbrough 1984) have similarly on the mid femora (Fig. 35; this structure is shaped mI cells but lack the thin, preapical, usuallythick and brown lOblack in other species dorsoposterior seta of the mid femur, and groups), anó the veins MI and M2 are slightly marginal scutellar bristles. Five undescribeó sigmoid, being slightly convex before the base South American species, in addition to O . of cell d and concave lOward the wing margino Iwlosenceus Schiner and O. exilis Curran, have Thus these converging veins produce a a thin mid femoral seta, and O. norma Curran constriction on the apical third of the mI cell anÓ O. neotropicus Curran have two-three long, (Fig. 34). The constriction of the mI cell is thinsetae on theepandr ium but each lacks other usually subequal lo the diameter of the cell attributes which would align them lO this species basally. The basal vein of cell mI is usually group. The costatus group may be the sister slightly oblique with its anterior end slightly grouplO the lineage giving rise lO O. spatulatus angled more lOwarÓthe wing base whereas the Curran. This relationship is evidenced by the posterior end is nearest the wing margino The general similarity of the body, the shape of cell apical margin of the wing is usually produced. mI anó the terminalia of both sexes. However, The epandrium has two lO furee long, thin setae O. spatulatus lacks the marginal scutellar or thick bristles (Figs. 2, 39, 134). The bristles, the long, proclinate, postocular bristles, gonostylus is slightly to strongly flat, and and the thin, preapical, dorsoposterior seta on usually wide in lateral profile. The rim of the the mid femur. Further stuóies are necessary lO gonocoxiteis usually a simple ridge or "elevated c1arify the relationship of the costatus species lip", although in a few species